Process for the preparation of 2, 5-dimethylefuran and furfuryl alcohol over ruthenium supported catalysts

Abstract

The present invention relates to an improved process for the preparation of 2,5-dimethylfuran and furfuryl alcohol over ruthenium supported catalysts. Further, the present invention disclosed a process for the selective hydrogenolysis of biomass derived 5-hydroxymethylfurfural (HMF) into 2,5-dimethylfuran (DMF) using Ru nanoparticles supported on NaY zeolite as a catalyst.

Claims

1. An improved process for the preparation of compound of formula 1 wherein the said process comprising reaction of compound of formula 2 in presence of ruthenium catalyst at 160-250° C. for 0.2-3 hours under hydrogen pressure in the range of 2-30 bar in a solvent wherein improvement is characterized in using ruthenium catalyst which comprises ruthenium nanoparticles in combination with transition metal supported on NaY zeolite ##STR00004## wherein, R=CH.sub.3 or H R′=CH.sub.3 or CH.sub.2OH ##STR00005## wherein, R=CH.sub.2OH or H.

2. The process as claimed in claim 1, wherein transition metals are selected from the group consisting of Cu, Ni, Re, Cr, Mn, Fe and Co in the range of 1-10 wt % of the catalyst.

3. The process as claimed in claim 1, wherein ruthenium catalyst supported on NaY zeolite is selected from 2% Ru—NaY, 2% Ru—K—NaY, 2% Ru—Rb—NaY, 2% Ru—Cs—NaY, 2% Ru—Mg—NaY, 2% Ru—Ca—NaY, 2% Ru—Sr—NaY, 2% Ru—Ba—NaY, Ru—Cu [1:3]/NaY.

4. The process as claimed in claim 1, wherein the solvent is tetrahydrofuran.

5. The process as claimed in claim 1, wherein compound of formula 1 is selected from the group consisting of 2,5-dimethylfuran and furfuryl alcohol.

6. The process as claimed in claim 1, wherein compound of formula 2 is selected from the group consisting of 5-hydroxymethylfurfural and furfural.

7. The process as claimed in claim 1, wherein mole ratio of 5-hydroxymethylfurfural and ruthenium catalyst is in the range of 150-250.

8. The process as claimed in claim 1, wherein conversion of compound of formula 2 is in the range of 90-100 mol %.

9. The process as claimed in claim 1, wherein yield of compound of formula 1 is in the range of 75-90 mol %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1. XRD profiles of (a) NaY zeolite (b) 1 wt % Ru—NaY (c) 2 wt % Ru—NaY and (d) 3 wt % Ru—NaY.

(2) FIG. 2. H.sub.2 Temperature-programmed reduction profiles of (a) 1 wt % Ru—NaY (b) 2 wt % Ru—NaY and (c) 3 wt % Ru—NaY.

(3) FIG. 3. H.sub.2 Temperature-programmed reduction profile of a) 2 wt % Ru—NaY b) 2 wt % Ru—K—NaY c) 2 wt % Ru—Rb—NaY and d) 2 wt % Ru—Cs—NaY.

(4) FIG. 4. SEM images of (a) NaY and (b) 0.2 wt % Ru—NaY.

(5) FIG. 5. TEM micrograph of 2 wt % Ru—NaY catalyst showing different Ru crystallite planes.

(6) FIG. 6. Effect of reaction temperature and time on HMF conversion. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY, 25 mg); H.sub.2 pressure (10 bar); solvent (THF, 25 mL).

(7) FIG. 7. Effect of reaction temperature and time on DMF yield. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY, 25 mg); H.sub.2 pressure (10 bar); solvent (THF, 25 mL).

(8) FIG. 8. Effect of solvent in liquid phase hydrogenolysis of HMF over 2 wt % Ru—NaY as a function of time. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY, 25 mg); temperature (220° C.); solvent (25 mL); H.sub.2 pressure (10 bar).

(9) FIG. 9. Effect of hydrogen pressure on DMF yield over 2 wt % Ru—NaY as a function of time. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY, 25 mg); temperature (220° C.); solvent (THF, 25 mL).

(10) FIG. 10. Effect of catalyst content on DMF yield as a function of time. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY); temperature (220° C.); H.sub.2 pressure (15 bar); solvent (THF, 25 mL).

(11) FIG. 11. Product distributions during HMF hydrogenolysis over various Ru metal containing catalysts. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (25 mg); temperature (220° C.); H.sub.2 pressure (15 bar); solvent (THF, 25 mL); reaction time (1 h).

(12) FIG. 12. HMF conversion and product yields as a function of reaction time at 170° C. Left: conversion of HMF. Right: product yields. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (2 wt % Ru—NaY, 25 mg); H.sub.2 pressure (10 bar); solvent (THF, 25 mL).

(13) FIG. 13. MF conversion and product yields as a function of reaction time at 170° C. Left: conversion of MF. Right: product yields. Reaction conditions: MF (1 mmol, 110 mg); catalyst (2 wt % Ru—NaY, 25 mg); H.sub.2 pressure (10 bar); solvent (THF, 25 mL).

(14) FIG. 14. The recyclability of 2 wt % Ru—NaY catalyst in hydrogenolysis of HMF. Reaction conditions: solvent (THF, 25 mL); temperature (220° C.); molar ratio of HMF to Ru (200); H.sub.2 pressure (15 bar); reaction time (1 h).

(15) FIG. 15. Effect of hydrogen pressure on DMF yield over 4.5 wt % Cu—NaY as a function of time. Reaction conditions: HMF (1 mmol, 126 mg); catalyst (4.5 wt % Cu—NaY, 50 mg); solvent (THF, 25 mL); temperature (220° C.).

DETAILED DESCRIPTION OF THE INVENTION

(16) The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.

(17) The present invention provide a process for the selective hydrogenolysis of biomass derived 5-hydroxymethylfurfural (HMF) into 2,5-dimethylfuran (DMF) using Ru nanoparticles supported on NaY zeolite as a catalyst.

(18) Further, the present invention provides a process for the preparation of 2,5-dimethylfuran with improved yield comprising the reaction of 5-hydroxymethylfurfural with ruthenium catalyst at 160-250° C. for 0.2-3 hours at hydrogen pressure from 2-30 bar in the presence of a solvent, wherein; said ruthenium catalyst comprises ruthenium nanoparticles either alone or in combination with transition metals supported on NaY zeolite.

(19) The ruthenium catalyst supported on NaY zeolite is selected from 2 wt % Ru—NaY, 2 wt % Ru—K—NaY, 2 wt % Ru—Rb—NaY, 2 wt % Ru—Cs—NaY, 2 wt % Ru—Mg—NaY, 2 wt %/Ru—Ca—NaY, 2 wt % Ru—Sr—NaY, 2 wt % Ru—Ba—NaY, Ru—Cu [1:3]/NaY.

(20) The present invention provides a process for 100% conversion of HMF with >50% selectivity to DMF, wherein said catalyst comprises 1-10 wt % metal exchanged NaY zeolite, wherein the metals are selected from noble metals and transition metals, said noble metals selected from Ru, Pt, Pd, Rh, Au, Ag, Os or Ir either alone or combination thereof in the range of 0.5-5 wt % of the catalyst, said transition metals selected from Cu, Ni, Re, Cr, Mn, Fe or Co either alone or combination thereof in the range of 1-10 wt % of the catalyst at 160-250° C., 0.2-3 hours at 2-30 bar in the presence of a solvent.

(21) The catalysts may contain faujasite type zeolite that has an exchangeable alkali and alkaline earth metals selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr or Ba either alone or combination thereof in the range of 1-10 wt % of the catalyst with noble metals and/or transition metals.

(22) The said catalyst is recyclable at least 5 times with no appreciable loss in activity and due to its high activity and reusability it has excellent potential for the conversion of biomass into biofuels.

(23) The solvent is selected from polar protic solvent, said polar protic solvent is preferably 2-propanol; polar aprotic solvent, said polar aprotic solvent is selected from THF (tetrahydrofuran), 1,2-DME (1,2-dimethoxyethane), CH.sub.3CN (acetonitrile) or DMSO (dimethyl sulphoxide); or non-polar solvent, said non polar solvent is preferably toluene.

EXAMPLES

(24) The following examples are given by way of illustration of the working if the invention is actual practice and shall not be construed to limit the scope of the present invention in anyway.

Example 1

Catalyst Preparation

(25) (A) Synthesis of M-NaY Catalyst (M=Ru, Pd, Pt or Rh):

(26) Ruthenium catalyst supported on NaY zeolite was synthesized by ion exchanged method which includes following steps. In the first step, ruthenium cations were introduced into NaY zeolite by ion-exchange method. In typical synthesis 1.96 g of NaY (CBV—100, Si/Al ratio—2.5) was dispersed in 20 mL deionized water and 8 mL RuCl.sub.3 solution (Ru content 5 mg/ml, for 2 wt % Ru) and this slurry was stirred for 3 h at 80° C. temperature. The mixture was then cooled, filtered and washed until no chloride ions were detected. The remnant was dried in oven at 100° C. for 10 h. Subsequently, solid (Ru.sup.+3/NaY) was reduced by NaBH.sub.4 (Ru/NaBH.sub.4=1:4 mol mol-1) in ethanol by continuous stirring at room temperature for 3 h. The sample was filtered, washed two times with 30 mL de-ionized water followed by drying in oven at 100° C. for 10 h. Similar procedure was adopted for the preparation of 1 wt % Ru—NaY and 3 wt % Ru—NaY by varying the amount of RuCl.sub.3 in solution. Further, 2 wt % Pt—NaY, 2 wt % Rh—NaY and 2 wt %/Pd—NaY catalysts were also prepared by adopting similar ion exchanged process. The ruthenium, platinum, rhodium and palladium content of the samples were estimated using inductively coupled plasma optical emission spectrophotometry, ICP-OES (Spectro Arcos).

(27) (B) Synthesis of 5 wt % Cu—NaY Catalyst:

(28) 4.75 g of NaY Zeolite (CBV—100, Si/Al ratio—2.5) was dispersed in 50 ml of distilled water along with 1.01 g of Cu(NO.sub.3).sub.2.3H.sub.2O (total Cu content is 250 mg, for 5 wt % Cu loading), the above mixture was stirred for 5 h at 80° C. The sample was cooled, filtered and washed two times with deionized water and the remnant was dried in oven at 100° C. for 10 h. Solid material was calcined in air at 400° C. for 4 h followed by reduction under hydrogen atmosphere at 400° C. for 4 h.

(29) (C) Synthesis of Ru—Cu [1:3]/NaY:

(30) 3.83 g of NaY Zeolite (CBV—100, Si/Al ratio—2.5) was dispersed in 40 ml of distilled water along with 8 ml of ruthenium chloride solution (Ru is 5 mg/ml, 40 mg of Ru metal) and 0.496 g of Cu(NO.sub.3).sub.2.3H.sub.2O salt (total Cu content is 120 mg), the above mixture was stirred for 3 h at 80° C. The sample was cooled, filtered and washed until no chloride ions were detected. The wet cake was dried in oven at 100° C. for 10 h and subsequently calcined in air at 300° C. for 2 h followed by reduction under hydrogen atmosphere at 400° C. for 4 h.

(31) (D) Synthesis of 2 wt % Ru—K—NaY:

(32) a) Preparation of 5% K—NaY from NaY:

(33) 5 g NaY Zeolite (CBV—100, Si/Al ratio—2.5) was dispersed in 50 ml distilled water along with 1.059 g of KNO.sub.3 (0.0108 moles of K) and stirred for 3 h at 80° C. The sample was then filtered, washed with deionized water and the remnant was dried in oven at 100° C. for 10 h. Solid material obtained was calcined in air at 400° C. for 4 h.

(34) (b) Preparation of 2 wt % Ru—K—NaY from 5% K—NaY:

(35) 3.92 g 5% K—NaY was dispersed in 40 ml of distilled water along with 16 ml of RuCl.sub.3 solution (Ru content is 5 mg/ml, 80 mg of Ru metal), the above mixture was stirred for 3 h at 80° C. The sample was then filtered, washed until no chloride ions were detected and the remnant was dried in oven at 100° C. for 10 h. Ion exchanged material was reduced by NaBH.sub.4 (Ru/NaBH.sub.4=1:4 mol mol.sup.−1) in ethanol solution followed by drying in oven at 100° C. for 10 h. Similar procedure was adopted to prepare 2 wt % Ru—Rb—NaY from 5% Rb—NaY, 2 wt % Ru—Cs—NaY from 5% Cs—NaY, 2 wt % Ru—Ca—NaY from 5% Ca—NaY, 2 wt % Ru—Sr—NaY from 5% Sr—NaY and 2 wt % Ru—Ba—NaY from 5% Ba—NaY catalyst by ion exchange method followed by reduction in NaBH.sub.4 solution at room temperature.

(36) (E) Characterization of the catalysts:

(37) E.1. X-Ray Diffraction

(38) Powder diffraction patterns of different Ru metal containing NaY zeolite samples, along with parent NaY zeolite are shown in FIG. 1. The similarity in the XRD patterns of the prepared ruthenium metal exchanged samples as compared to the starting material, NaY zeolite, indicates that the zeolite structure was retained even after ion-exchange. The diffractograms show typical diffraction patterns of the faujasite framework.

(39) E.2. BET Surface Area and H.sub.2 Chemisorption

(40) The similarity in the surface area values for the Ru exchanged NaY catalyst and the parent zeolite suggest that the NaY (Entry 1, 2, 3 and 4, Table 1) did not undergo any substantial damage during catalyst preparation method. However, there is significant decrease in the specific surface area of the catalysts as we move from 2 wt % Ru—NaY (851 m.sup.2/g) to 2 wt % Ru—Cs—NaY (602 m.sup.2/g). This decrease in surface area is attributed to increase in size of exchangeable alkali metal cations from Na.sup.+ (102 pm) to Cs.sup.+ (167 pm) ions, which is also reflected in continuous decrease in pore volume. Metal dispersion values were obtained by a H.sub.2 chemisorption method. The dispersion values (%) for the Ru exchanged NaY samples (Entry 2, 3 and 4, Table 1) are: 1 wt % Ru—NaY, 47.4%; 2 wt % Ru—NaY, 53.2% and 3 wt % Ru—NaY, 19.3%. The higher Ru metal dispersion was obtained for 2 wt % Ru—NaY samples. But, further increase in Ru loading (3 wt % Ru loading) led to bigger Ru crystallites (6.9 nm) with low (19.3%) metal dispersion.

(41) TABLE-US-00001 TABLE 1 Physicochemical property of NaY and Ru exchanged NaY catalysts. Ru/Cu BET Total Average metal surface pore Metal crystallite content area volume dispersion size Entry Catalyst (%).sup.[a] (m.sup.2/g) (cc/g) (%).sup.[b] (nm).sup.[b] 1 NaY — 886 0.35 — — 2 1 wt % Ru—NaY 0.97 861 0.34 47.4 2.8 3 2 wt % Ru—NaY 1.98 851 0.34 53.2 2.5 4 3 wt % Ru—NaY 2.95 827 0.33 19.3 6.9 5 2 wt % Ru—K—NaY 1.92 776 0.30 48.5 2.7 6 2 wt % Ru—Rb—NaY 1.95 686 0.27 45.2 3.0 7 2 wt % Ru—Cs—NaY 1.91 602 0.23 41.4 3.2 8 5 wt % Cu—NaY 4.50 813 0.31 — — .sup.[a]Chemical composition determined by ICP-OES. .sup.[b]Determined from H.sub.2 chemisorption analysis. The catalyst was reduced at 200° C. during metal dispersion experiment.
E3. Temperature Programmed Reduction:

(42) Temperature programmed reduction (TPR) profiles of ruthenium exchanged NaY zeolite samples and alkali metal modified (K, Rb and Cs) Ru—NaY samples were evaluated and results are shown in FIG. 2 and FIG. 3, respectively. Only one broad peak in the 70-150° C. temperature regions was observed for all the samples, except for 3 wt % Ru—NaY sample. Two peaks were observed for 3 wt % Ru—NaY in the range of 80-170° C., which may be correspond to two different locations of ruthenium cations in zeolite pores/cavities.

(43) E.4. Scanning Electron Microscopy (SEM):

(44) SEM analysis of parent NaY zeolite and 2 wt % Ru—NaY sample are shown in FIG. 4. The micrograph demonstrates that the morphology of 2 wt % Ru—NaY catalyst did not change with respect to that of NaY zeolite, suggesting that no morphological transformations occurred during the ruthenium ion exchange into NaY zeolite.

(45) E.5. Transmission Electron Microscopy (TEM):

(46) The TEM images of 2 wt % Ru—NaY is shown in FIG. 5. Micrograph of 2 wt % Ru—NaY catalyst shows that Ru particles are well dispersed on NaY support with average crystallite size of 2 to 3 nm, which is in accordance with H.sub.2 chemisorption study.

(47) E.6. Catalytic Activity of 2 wt % Ru—NaY Catalyst for Hydrogenolysis of HMF to DMF with all Details and Yield and Selectivity

(48) The hydrogenolysis of HMF over 2 wt % Ru—NaY catalyst gave the DMF yield of 78 mol % at 100 mol % HMF conversion with DMF selectivity of 78% at optimum reaction conditions (220° C., THF, 15 bar H.sub.2 and 1 h of reaction time).

(49) E.6. Recyclability Study Over 2 wt % Ru—NaY Catalyst:

(50) Catalyst recyclability is of great importance to use it in an industrial process. The recyclability of the 2 wt % Ru—NaY catalyst was evaluated by repeating the reaction with the same catalyst at least five times. These results are shown in FIG. 14. Results show that the catalytic performance of the 2 wt % Ru—NaY catalyst remains almost same even after being used for five times, indicating the good stability of the catalyst.

Example-2

Catalytic Activity Over 4.5 wt % Cu—NaY for Hydrogenolysis of HMF to DMF

(51) Hydrogenolysis of HMF to DMF was also studied over 4.5 wt % Cu—NaY catalyst at 220° C. by changing the hydrogen pressure from 5-30 bar, the results are shown in FIG. 15. As it can be seen from FIG. 15, DMF yield continuously increased with the time on stream at lower hydrogen pressure (5, 10, 15 and 18 bar). With further increase in pressure (22 bar), DMF yield increased with time and reaches to maximum after 5 h of reaction time, which is 64.5 mol %. However, with further increase in hydrogen pressure (26 bar), DMF yield increases up to 1 h and then decreases with the reaction time. Furthermore, when reaction was conducted again at higher hydrogen pressure (30 bar) continuous decreased in DMF yield was observed, indicating that at higher pressure ring hydrogenation of DMF was favoured leading to the formation of DMTHF. Finally, 22 bar H.sub.2 pressure was found to be optimum H.sub.2 pressure to achieve 64.5 mol % DMF yield at 220° C. after 5 h of reaction time.

Example-3

Catalytic Activity Over Different Noble Metal for Hydrogenolysis of HMF to DMF

(52) All the catalysts were tested under at optimum reaction conditions obtained for of 2% Ru—NaY catalyst. Six principal products were observed: DMF, DMTHF, BHMF (2,5-bis(hydroxymethyl)furan), MF (5-methyl furfural), MFA (5-methyl furfuryl alcohol) and MFU (2-methyl furan). Other unknown products were also observed. The HMF conversion after 1 h of reaction ranged from 92 mol % for Rh—NaY to 100 mol % for Pt—NaY and Pd—NaY (Table 2). The DMF yield, the desired final product, was highest for Pd—NaY, 49.3 mol %. DMTHF, the hydrogenated compound of DMF was formed in more amount when platinum (4 mol %) and rhodium (10.7 mol %) was used as catalysts, whereas little amount of DMTHF (1.1 mol %) was observed when palladium based catalyst was used. Indicating that at the same weight loading platinum and rhodium catalysts were more active compared to the palladium catalyst for complete hydrogenation of DMF to DMTHF. Higher yield (10 mol %) of MFU was obtained for platinum based catalyst compare to rhodium and palladium as catalysts; shows that platinum catalyze both hydrogenation and carbon-carbon scission reaction. Furthermore, when platinum was used as catalyst, the majority of the HMF was converted to unidentified products. The GC chromatogram of the reaction mixture did not reveal any significant peaks, which may indicate that the undetected carbon is in the form of insoluble polymers, were formed on the catalyst surface. These insoluble polymers can be formed by the loss of formaldehyde from BHMF, followed by furfuryl alcohol polymerization.

(53) TABLE-US-00002 TABLE 2 Product distribution for Hydrogenolysis of HMF over different noble metal catalysts.sup.[a]. Conv. Yield (mol %) Entry Catalyst (mol %) DMF DMTHF BHMF MFA MF MFU Other.sup.[b] 1 2% Pt—NaY 100 30.4 4.0 7.8 14.0 6.6 10.0 27.2 2 2% Rh—NaY 92 40.1 10.7 11.5 12.8 2.6 2.2 12.1 3 2% Pd—NaY 100 49.3 1.1 15.6 19.0 2.3 1.2 11.5 .sup.[a]Reaction conditions: HMF (1 mmol, 126 mg); catalyst (25 mg); temperature (220° C.); H.sub.2 pressure (15 bar); solvent (THF 25 mL); reaction time (1 h). .sup.[b]It includes MTHFA, OMBM, FA, BHMTHF and some other unidentified compounds.

Example-4

Hydrogenolysis of HMF to DMF

(54) In a typical experiment, the reactor was charged with 1 mmol (126 mg) of HMF, solvent (25 mL), n-decane (0.2 g, internal standard) and required amount of freshly reduced catalyst. The reactor contents were mixed thoroughly and the reactor was sealed, purged 2-3 times with hydrogen and filled with 2-30 bar hydrogen pressure. Subsequently, the reaction vessel was heated under stirring at 160-250° C. for a 0.2-3 hours. Liquid samples were withdrawn periodically during the reaction and analyzed by GC (Agilent 7890A) equipped with a flame ionization detector (FID) having CP Sil 8 CB capillary column (30 m length, 0.25 mm diameter).

Example-5

Catalytic Activity Over Ru—Cu [1:3]/NaY for Hydrogenolysis of HMF to DMF

(55) Ru—Cu [1:3]/NaY catalyst was prepared by simple ion exchanged method and tested for the selective hydrogenolysis of HMF to DMF under optimum reaction conditions obtained for 2 wt % Ru—NaY catalyst (temperature (220° C.), solvent (THF), H.sub.2 pressure (15 bar)) as a function of reaction time and the results are shown in Table 3. It can be seen that DMF yield increases with the progress of reaction, suggesting that intermediates like BHMF, MFA and MF are converting to DMF with prolonged reaction time. After 2.5 h of reaction time, a maximum of 67.5 mol % DMF was obtained (Entry 5, Table 3), which decreased on further increasing reaction time. Overall, activity of Ru—Cu[1:3]/NaY catalyst for DMF formation was found to be lower when compared to 2 wt % Ru—NaY catalyst.

(56) TABLE-US-00003 TABLE 3 Catalytic hydrogenolysis of HMF to DMF over Ru—Cu[1:3]/NaY catalyst.sup.[a] Yield (mol %) Entry Time (h) Conv. (mol %) DMF DMTHF BHMF MFA MF MFU Other.sup.[b] 1 0.5 92.6 35.5 1.6 31.9 11.0 3.2 1.2 8.2 2 1 97.1 47.0 2.3 17.2 14.3 3.1 1.2 12.0 3 1.5 100 55.0 3.2 9.8 15.1 2.2 1.0 13.7 4 2 100 62.3 4.6 2.6 9.3 1.5 2.0 17.7 5 2.5 100 67.5 6.4 0 4.1 0 2.4 19.6 6 3 100 59.3 10.5 0 0 0 4.2 26.0 .sup.[a]Reaction Conditions: HMF (1 mmol, 126 mg); catalyst (Ru—Cu [1:3]/NaY, 25 mg); solvent (THF, 25 ml); temperature (220° C.); H.sub.2 pressure (15 bar). .sup.[b]It includes MTHFA, OMBM, FA, BHMTHF, and some other unidentified compounds.

Example-6

Catalytic Hydrogenation of Furfural to Furfuryl Alcohol Over 2 wt % Ru—NaY Catalyst

(57) Furfural, which is a dehydration product of xylose can be converted to furfuryl alcohol (FFA), 2-methyl furan (MFU) and 2-methyltetrahydrofuran (MTHF). We also explored the efficiency of 2 wt % Ru—NaY catalyst for selective hydrogenation of furfural to FFA, whose results are shown in Table 4. The catalytic activity was tested by conducting the reaction in the temperature range of 150-180° C., 5-20 bar of H.sub.2 pressure and with THF as solvent. It can be observed from Table 4 that temperature played significant role in furfural conversion and FFA yield. Reaction temperature of 165° C. was found to be optimum temperature to achieve 94.3% furfural conversion and 86.1% FFA yield after 8 h of reaction time (Entry 6, Table 4).

(58) TABLE-US-00004 TABLE 4 Chemo-selective hydrogenation of furfural to furfuryl alcohol (FFA) with 2 wt % Ru—NaY catalyst..sup.[a] Furfural FFA FFA THFA Temp Time conv. yield selectivity yield Other.sup.[e] Entry (° C.) (h) (%) (%) (%) (%) (%)  1.sup.[b] 150 4 34.4 28.2 82.1 1.1 5.1  2 150 5 58.7 42.2 71.9 2.0 14.5  3 180 5 94.3 61.5 65.2 6.5 26.3  4 165 4 63.5 58.0 91.2 3.7 1.8  5 165 6 78.1 72.5 94.1 3.4 2.2  6 165 8 94.3 86.1 91.3 5.1 3.1  7 175 4 69.0 62.9 91.1 3.1 3.0  8 175 6 84.8 77.0 86.4 5.3 2.5  9 175 8 100 79.5 79.5 10.0 10.5 10.sup.[c] 175 6 100 46.7 46.7 24.1 29.2 11.sup.[d] 175 6 100 5.8 5.8 53.5 40.7 .sup.[a]Reaction conditions: furfural (4 mmol, 0.384 g); catalyst (2 wt % Ru—NaY, 30 mg); H.sub.2 pressure (10 bar); solvent (THF, 25 mL); .sup.[b]5 bar; .sup.[c]15 bar and .sup.[d]20 bar. .sup.[e]Includes MFU, furan, THF and MTHF.

ADVANTAGES OF INVENTION

(59) a. DMF is a good alternative to bio-ethanol. DMF has superior properties compared to ethanol. b. A catalyst that is highly efficient and economical in terms of DMF yield. c. The catalyst is re-usable and very easy to prepare, store and use in the application. d. The H.sub.2 pressures and temperatures used in the process are moderate and do not need any expensive equipment for carrying out the process.